1. Field of the Invention
The present invention relates to water treatment systems, and more particularly to the control assemblies used to regulate the operation of such systems.
2. Description of the Related Art
Water treatment systems conventionally include tanks that are used to hold media through which water is directed for treatment. A common water treatment method involves the use of a resin material such as polystyrene divinyl benzene to form small beads which act as a replenishable ion exchange medium. For example, the beads, or media, may be used to exchange sodium ions for calcium and magnesium ions and, after the sodium ions attached to the media have been depleted (being replaced by calcium or magnesium ions), a brinish solution containing sodium is used to exchange the calcium and magesium ions on the media for sodium ions. The media may, alternatively, be utilized in a different ion exchange process and be replenished with an appropriate ionic solution.
Typically, the media is held in a water treatment tank and untreated water is introduced into the tank near its upper end. A center tube is vertically disposed in the tank and withdraws water from near the bottom of the tank. Thus, the untreated water passes through the media held in the tank, ensuring contact between the media and the water and, therefore, treatment of the water.
After the media has been depleted a regeneration cycle is required and typically includes a cleansing backwash cycle prior to the introduction of an ionic solution into the tank to replenish the media. During the normal operations of the tank, the media bed can become compacted as the media beads settle towards the bottom of the tank. It is also possible that bridging can occur in the media bed; this is an undesirable process by which the untreated water entering the tank creates small channels in the media bed leading to the center tube inlet. During the backwash cycle a fluid, such as untreated water, is introduced into the tank through the center tube and then flows upward through the media bed, lifting the media bed counteracting the settling and bridging which has occurred and removing any debris that may have accumulated in the bed.
After the backwash cycle is complete, the brinish solution is introduced into the tank to recharge the media. The brine tank is typically refilled with water after the brining phase of the regeneration cycle is completed. A rinsing cycle which resettles the media within the tank and flushes the brinish solution from the tank is also often used near the completion of the regeneration cycle.
A control valve assembly is typically located on the top of the tank holding the media and is used to regulate the flow of fluid through the tank. These assemblies may include a motorized timer and mechanical gears or a circuit board to regulate the opening and closing of the appropriate valves.
U.S. Pat. No. 3,616,820 (Fleckenstein) discloses a valve body having inlet, outlet, drain, tank connecting and brining passages therein. A slidable piston is disposed in the valve body and is movable to various positions within the valve body to connect the passages for normal service such as backwashing, regeneration, and brine tank filling. The piston is driven by a drive motor, and a crank is operable by the motor for shifting the piston through the various positions. The drive motor, timing motor and switch are mounted in a housing which is attached to the valve body. The disadvantage of such an arrangement is that the various components are difficult to access and service.